1. Technical Field
The present disclosure relates to a probe structure. More particularly, the present disclosure relates to a probe module having multi-tier needles with angle variation.
2. Description of Related Art
In a test of semiconductor chips, a tester needs to contact devices under test (DUT), such as chips, through probe cards. Test results of the devices under test can be obtained by signal transmissions and electrical signal analysis. A probe card often includes several precision needles arranged thereon. Each of the needles usually corresponds to a specific electrical connection pad of a chip (i.e. a device under test). When the needles contact the corresponding electrical connect (i.e., pads, bump, etc.), the test signals of the tester having the probe card can be correctly transmitted. Simultaneously, the control and analysis procedures of the tester and the probe card are operated in coordination to achieve the purpose of testing the electrical characteristics of the device under test.
However, along with the progress in electrical element, the density of the electrical concacts of the chip is gradually increased, such that the density and the tier number of the needles need to be increased as well. FIGS. 1A and 1B are structure schematic views of multi-tier needle structures of conventional probe modules. Referring to FIG. 1A, a chip 100 has two electrical concacts 100a, 100b thereon, and the probe module has a first probe-needle row and a second probe-needle row. The first probe-needle row has a plurality of needles (12-1, 12-2), and the second probe-needle row has a plurality of needles (12-3, 12-4). The end portions 12b of the needles are respectively connected to the electrical concacts 100a, 100b. An included angle is formed between the arm segment 12d and the contact segment 12e of each of the needles. As far as the needles at the same row are concerned, such as the second probe-needle row, the included angle θ1 of the needle 12-3 is smaller than the included angle θ2 of the needle 12-4. Moreover, in the first probe-needle row, the included angle θ1 of the needle 12-1 is smaller than the included angle θ2 of the needle 12-2. In addition, as far as the corresponding needles at different rows, the included angles of the needles are the same. For example, the needle 12-1 of the first probe-needle row and the needle 12-3 of the second probe-needle row have the same included angle θ1, and the needle 12-2 of the first probe-needle row and the needle 12-4 of the second probe-needle row have the same included angle θ2. Furthermore, in FIG. 1B, the included angles of the needles are the same, but the lengths of the contact segments of the needles are different.